Picture / Image: The Viaduct, Porthkerry Park, Barry. Porthkerry Viaduct is a railwayviaduct nearBarry in theVale of Glamorgan, Wales. [4] The viaduct eventually re-opened on 8 January 1900. [3] A two and a half mile loop line diversion was quickly built around the north of the valley, whilst repairs and underpinning were entrusted to Price and Wills, builders of the no. 2 dock inBarry.